bug#11348: 24.0.95; TAB-completion in shell-command produces d:\/foo on MS-Windows

[Eli Zaretskii <eliz@gnu.org>]

> From: Chong Yidong <cyd@gnu.org>
> Cc: 11348@debbugs.gnu.org
> Date: Fri, 04 May 2012 23:46:31 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> The black magic occurs in `comint--complete-file-name-data' in
> >> comint.el.
> >
> > That function doesn't get called when I use the recipe to reproduce
> > the problem.  At least instrumenting it with Edebug doesn't activate
> > Edebug inside that function.
> 
> Whoops.  Then maybe the problem is in pcomplete-completions-at-point,

I see in pcomplete-completions-at-point that typing "M-! cd d:\gnu TAB"
causes pcomplete-stub on entry to pcomplete-completions-at-point to get
the value "d:gnu", whereas if I type "M-! cd d:/gnu TAB", the value of
pcomplete-stub is "d:/gnu".

Sounds like whoever computes pcomplete-stub is the culprit: they treat
the backslash as an escape character (or so it seems).

> As an experiment, could you try removing
> pcomplete-completions-at-point from shell-dynamic-complete-functions
> and see if there is anything different?

This works better, it produces "cd d:\gnu/ ", which is ugly, but
correct.